Beam design to mitigate interference at cell edges for shared spectrum systems

ABSTRACT

Methods and systems for citizens broadband radio service (CBRS) device (CBSD) interference management is described. A method for managing shared spectrum network interference includes determining, by a Citizens Broadband Radio Service (CBRS) device (CBSD) granted shared spectrum by a spectrum access system (SAS), a number of mobile devices in a defined number of regions in a cell covered by the CBSD, assigning, by the CBSD, a greater number of antennas to a cell edge region from the defined number of regions than a remaining regions in the defined number of regions, and assigning, by the CBSD, at least 8 antennas to each mobile device of a defined number of mobile devices of the number of mobile devices in the cell edge region to transmit non-overlapping and directive beams to mitigate interference at the cell edge region.

TECHNICAL FIELD

This disclosure relates to wireless communications. More specifically,using beam design for interference management in shared spectrumsystems.

BACKGROUND

Wireless telecommunications or radio access technologies (RATs) can useshared radio frequency spectrum for communications between mobiledevices and wireless telecommunications networks. For example, licensedspectrum is used for third generation (3G), fourth generation (4G), andfifth generation (5G) wireless communications.

Citizens Broadband Radio Service (CBRS) spectrum is a type of unlicensedspectrum or shared radio frequency spectrum which is shared betweenmultiple entities including government users (such as the military),licensed users, and non-licensed users. CBRS is a multi-tiered wirelessband between 3.550 MHz and 3.700 MHz. In particular, CBRS is athree-tiered access framework including incumbent users (i.e., federal,military, and the like), priority access users (winning auctionbidders), and general authorized access users, where the general usersare permitted to use any portion of the CBRS spectrum not assigned to ahigher tier user and may also operate opportunistically on unusedpriority access spectrum. Availability of CBRS spectrum dynamicallychanges depending on use by higher priority entities. Higher tier usersare protected from lower tier users using a centralized spectrum accesssystem (SAS), which may be a federal or commercial entity. The SASauthorizes or grants spectrum to access points known as CBRS Devices(CBSDs) and performs interference management to protect higher tierusers. This protection may include, for example, dropping CBSDs whichare general authorized access users. In summary, CBRS is an interferencelimited network which means that the performance of the network and thedata sent to CBRS subscribers is limited by the amount of interferencethe CBRS users or subscribers experience in the frequency band ofoperation.

Performance of a service provider network using CBRS spectrum isaffected by the amount of interference the CBRS users or subscribersexperience in the frequency band of operation. Proactive interferencemanagement by service providers is needed to avoid service interruptionor lose of coverage.

SUMMARY

Disclosed herein are methods and systems for interference management ata base station. A method for managing shared spectrum networkinterference includes determining, by a Citizens Broadband Radio Service(CBRS) device (CBSD) granted shared spectrum by a spectrum access system(SAS), a number of mobile devices in a defined number of regions in acell covered by the CBSD, assigning, by the CBSD, a greater number ofantennas to a cell edge region from the defined number of regions than aremaining regions in the defined number of regions, and assigning, bythe CBSD, at least 8 antennas to each mobile device of a defined numberof mobile devices of the number of mobile devices in the cell edgeregion to transmit non-overlapping and directive beams to mitigateinterference at the cell edge region.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure is best understood from the following detaileddescription when read in conjunction with the accompanying drawings. Itis emphasized that, according to common practice, the various featuresof the drawings are not to scale. On the contrary, the dimensions of thevarious features are arbitrarily expanded or reduced for clarity.

FIG. 1 is a diagram of an example of a citizens broadband radio service(CBRS) system in accordance with embodiments of this disclosure.

FIG. 2 is an example of beams with increasing antennas in accordancewith embodiments of this disclosure.

FIG. 3 is a block diagram of an example of a CBRS device (CBSD) inaccordance with embodiments of this disclosure.

FIG. 4 is a block diagram of an example of a device in accordance withembodiments of this disclosure.

FIG. 5 is a flowchart of an example method for CBRS network interferencemanagement using a CBSD in accordance with embodiments of thisdisclosure.

DETAILED DESCRIPTION

Reference will now be made in greater detail to embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numerals will be usedthroughout the drawings and the description to refer to the same or likeparts.

As used herein, the terminology “computer” or “computing device”includes any unit, or combination of units, capable of performing anymethod, or any portion or portions thereof, disclosed herein. Forexample, the “computer” or “computing device” may include at least oneor more processor(s).

As used herein, the terminology “processor” indicates one or moreprocessors, such as one or more special purpose processors, one or moredigital signal processors, one or more microprocessors, one or morecontrollers, one or more microcontrollers, one or more applicationprocessors, one or more central processing units (CPU)s, one or moregraphics processing units (GPU)s, one or more digital signal processors(DSP)s, one or more application specific integrated circuits (ASIC)s,one or more application specific standard products, one or more fieldprogrammable gate arrays, any other type or combination of integratedcircuits, one or more state machines, or any combination thereof.

As used herein, the terminology “memory” indicates any computer-usableor computer-readable medium or device that can tangibly contain, store,communicate, or transport any signal or information that may be used byor in connection with any processor. For example, a memory may be one ormore read-only memories (ROM), one or more random access memories (RAM),one or more registers, low power double data rate (LPDDR) memories, oneor more cache memories, one or more semiconductor memory devices, one ormore magnetic media, one or more optical media, one or moremagneto-optical media, or any combination thereof.

As used herein, the terminology “instructions” may include directions orexpressions for performing any method, or any portion or portionsthereof, disclosed herein, and may be realized in hardware, software, orany combination thereof. For example, instructions may be implemented asinformation, such as a computer program, stored in memory that may beexecuted by a processor to perform any of the respective methods,algorithms, aspects, or combinations thereof, as described herein.Instructions, or a portion thereof, may be implemented as a specialpurpose processor, or circuitry, that may include specialized hardwarefor carrying out any of the methods, algorithms, aspects, orcombinations thereof, as described herein. In some implementations,portions of the instructions may be distributed across multipleprocessors on a single device, on multiple devices, which maycommunicate directly or across a network such as a local area network, awide area network, the Internet, or a combination thereof.

As used herein, the term “application” refers generally to a unit ofexecutable software that implements or performs one or more functions,tasks or activities. For example, applications may perform one or morefunctions including, but not limited to, telephony, web browsers,e-commerce transactions, media players, travel scheduling andmanagement, smart home management, entertainment, and the like. The unitof executable software generally runs in a predetermined environmentand/or a processor.

As used herein, the terminology “determine” and “identify,” or anyvariations thereof includes selecting, ascertaining, computing, lookingup, receiving, determining, establishing, obtaining, or otherwiseidentifying or determining in any manner whatsoever using one or more ofthe devices and methods are shown and described herein.

As used herein, the terminology “example,” “the embodiment,”“implementation,” “aspect,” “feature,” or “element” indicates serving asan example, instance, or illustration. Unless expressly indicated, anyexample, embodiment, implementation, aspect, feature, or element isindependent of each other example, embodiment, implementation, aspect,feature, or element and may be used in combination with any otherexample, embodiment, implementation, aspect, feature, or element.

As used herein, the terminology “or” is intended to mean an inclusive“or” rather than an exclusive “or.” That is unless specified otherwise,or clear from context, “X includes A or B” is intended to indicate anyof the natural inclusive permutations. That is if X includes A; Xincludes B; or X includes both A and B, then “X includes A or B” issatisfied under any of the foregoing instances. In addition, thearticles “a” and “an” as used in this application and the appendedclaims should generally be construed to mean “one or more” unlessspecified otherwise or clear from the context to be directed to asingular form.

Further, for simplicity of explanation, although the figures anddescriptions herein may include sequences or series of steps or stages,elements of the methods disclosed herein may occur in various orders orconcurrently. Additionally, elements of the methods disclosed herein mayoccur with other elements not explicitly presented and described herein.Furthermore, not all elements of the methods described herein may berequired to implement a method in accordance with this disclosure.Although aspects, features, and elements are described herein inparticular combinations, each aspect, feature, or element may be usedindependently or in various combinations with or without other aspects,features, and elements.

Further, the figures and descriptions provided herein may be simplifiedto illustrate aspects of the described embodiments that are relevant fora clear understanding of the herein disclosed processes, machines,and/or manufactures, while eliminating for the purpose of clarity otheraspects that may be found in typical similar devices, systems, andmethods. Those of ordinary skill may thus recognize that other elementsand/or steps may be desirable or necessary to implement the devices,systems, and methods described herein. However, because such elementsand steps are well known in the art, and because they do not facilitatea better understanding of the disclosed embodiments, a discussion ofsuch elements and steps may not be provided herein. However, the presentdisclosure is deemed to inherently include all such elements,variations, and modifications to the described aspects that would beknown to those of ordinary skill in the pertinent art in light of thediscussion herein.

Disclosed herein are methods and systems for interference management ata shared spectrum base station. In implementations, the shared spectrummay be a Citizens Broadband Radio Service (CBRS) spectrum which iscontrolled or managed by a spectrum access system (SAS). The sharedspectrum base station can use a combination of antenna assignment,spatial diversity, and time diversity based on mobile devicedistribution and mobile device density to generate or form a beam for amobile device at a cell edge in a non-interfering manner from a point ofview of the SAS. The method may improve user experience when using theCBRS spectrum for connectivity and communications. For example, this mayprevent a CBRS device (CBSD) from being dropped by the SAS.

In implementations, a shared spectrum base station can form and transmitindependent non-overlapping beams at or below a shared spectrumtransmission power threshold. That is, for a mobile device, one highlydirected beam can be formed using more than four (4) of the antennasavailable on the shared spectrum base station. The highly directed beamcan be transmitted at high power levels but due to its narrow beamwidthcreates less interference to neighboring shared spectrum networks. Assuch, the beam is substantially invisible or negligible in terms ofinterference as viewed by the SAS. In implementations, the number ofantennas can be increased when the density of mobile devices at the celledge is high. High density meaning that the number of beams needed forthe number of mobile devices at the cell edge can result in interferencelevels noticeable by the SAS. Usage of additional antennas to generatethe beams can reduce the level of interference due to increasinglynarrower bandwidth beams. That is, presenting a non-localizedinterference pattern with respect to the SAS.

In implementations, a shared spectrum base station can determine anumber of mobile devices in each of a number of regions by checkingpower headroom reports sent by the mobile devices. The shared spectrumbase station can assign a number of antennas to each of the regionsbased on the number of mobile devices. The number of antennas can bere-assigned based on SAS messages, change in the number of mobiledevices in a region, or combinations thereof.

In implementations, antenna configurations and power resources of ashared spectrum base station can be used to manage interference in aCBRS network.

FIG. 1 is a diagram of an example architecture 1000 for CBRS networkinterference management. In an implementation, the architecture 1000 caninclude a first CBRS network 1100 and a second CBRS network 1200. Thefirst CBRS network 1100 can include a CBSD 1110 which may providewireless or cell coverage 1120. The second CBRS network 1200 can includea CBSD 1210 which may provide wireless or cell coverage 1220. The numberof CBRS networks, the number of CBSDs in a CBRS network, and thewireless coverage is illustrative and the architecture 1000 may includemore or less networks, each network may include more or less CBSDs, andthe wireless coverage can be any profile. The architecture 1000 mayinclude a SAS 1300 which is connected to or in communication(collectively “in communication with”) with each of the CBSDs 1100 and1200. A mobile device 1400 and a mobile device 1410 can be incommunication with one of the CBSDs 1100 and 1200. The communicationsbetween the mobile device 1400 and the mobile device 1410, particularCBSDs 1100 and 1200, and the SAS 1300 can include wired communications,wireless communications, or a combination thereof. In an implementation,the architecture 1000 may execute the techniques described in FIG. 5.The architecture 1000 is illustrative and may include additional, feweror different devices, entities and the like which may be similarly ordifferently architected without departing from the scope of thespecification and claims herein. Moreover, the illustrated devices mayperform other functions without departing from the scope of thespecification and claims herein.

The CBSDs 1100 and 1200 may be a base station, an access point, anaccess node or like device which enables radio communications accessbetween, for example, the mobile device 1400 and the mobile device 1410to other devices. Each CBSD 1100 and 1200 can be authorized and grantedspectrum allocation by the SAS 1300.

In implementations, the CBSDs 1100 and 1200 can be part of a serviceprovider system or multiple systems operator (MSO) which providesconnectivity and content to the mobile device 1400 and the mobile device1410, for example. In implementations, the CBSDs 1100 and 1200 can beoperated via or under a mobile virtual network operator (MVNO) whichprovides connectivity and content to the mobile device 1400 and themobile device 1410, for example. In implementations, the CBSDs 1100 and1200 can be owned and operated by the same MSOs or MVNOs. Inimplementations, the CBSDs 1100 and 1200 can be owned and operated bydifferent MSOs or MVNOs. Each of the CBSDs 1100 and 1200 can implementor use beamforming and beam steering along with massivemultiple-input/multiple-out (MIMO) technology (collectively “beamformingtechnology”) as specified for 5G wireless communications. with as. Inimplementations, the CBSDs 1100 and 1200 can have eight (8) or moreantennas, 100s of antennas, or more. The CBSDs 1100 and 1200 can use thebeamforming technology to generate a beam which is much narrower,enabling the CBSDs 1100 and 1200 to transmit radio frequency (RF) energyto the mobile devices 1400 and 1410, for example, more directly andefficiently. The greater the number of antennas used to form the beam,the narrower the beam as shown in FIG. 2, which illustrates differentmain lobes for beams 2000. For example, the main lobes for beams 2100,2200, 2300, and 2400 are increasingly narrower the number of beamsincreases from 1, 4, 8, and 16, respectively.

The mobile device 1400 and the mobile device 1410 can be, but is notlimited to, Internet of Thing (IoT) devices, sensors, end user devices,cellular telephones, Internet Protocol (IP) devices, mobile computers,laptops, handheld computers, personal media devices, smartphones,notebooks, notepads, and the like can be provisioned for operation witha MSO, MVNO, or other like service provider.

The SAS 1300 enables access to the CBRS spectrum and dynamically managesthe spectrum for optimal use, efficiency, and compliance with CBRSrules. The SAS 1300 communicates with each CBSD for registration, grantallocation/deallocation and interference management. The SAS 1300 canperform interference analysis based on the power measurements receivedfrom mobile device(s) and make allocation and deallocation decisionsbased on the interference. The SAS 1300 may be operated be a commercial,federal entity, or some combination thereof.

In typical 5G networks, at least one beam is created for each mobiledevice in the network. A beam is created using at least four (4)antennas. For example, if there are 100 antennas on a CBSD, then theCBSD can create at most 25 beams at the same time to service 25 mobiledevices if only one beam is dedicated to each mobile device. If thereare 2 beams dedicated to each mobile device, then only 12 mobile devicescan be served at the same time. Assigning a different number of beams toeach mobile device has drawbacks in terms of interference, especiallyfor mobile devices at a cell edge. For example, a SAS grants spectrum toa CBSD 1110 and 1210, which can transmit 47 dBm of total power for every10 MHz of spectrum dedicated to the CBSD 1110 and 1210, respectively. Ifmore than one beam is assigned to a cell edge mobile device, such as forexample mobile device 1400, by the CBSD 1110, for example, then thetotal power of these beams might go above the interference limit ortransmit power threshold, i.e., with respect to a neighbor network, suchas for example CBRS network 1200. In this instance, the SAS 1300, forexample, can deallocate the CBSD 1110, resulting in loss of coverage1120.

Interference management by the CBSDs can be used to decrease the chanceof a CBSD from being deallocated. A CBSD, for example, CBSD 1110, candetermine the number of mobile devices in different regions based onpower headroom reports received from each mobile device in communicationwith the CBSD 1110. The regions can include a cell edge, a cell middle,and a cell near relative to the location of the CBSD. The number ofregions can be more without departing from the scope of the claims andspecification. The power headroom reports include reported valuesranging from 0 to 63, for example. The CBSD 1110 can identify a mobiledevice with a power headroom value of 0 as being on the cell edge,identify a mobile device with a power headroom value from 3 to 5 asbeing on the cell middle, and identify a mobile device with a powerheadroom value of 6 and greater as being on the cell near.

If a CBSD has N antennas, the CBSD 1110 can assign N₁ antennas to adefined number of the mobile devices on the cell edge and assign N₂antennas to the mobile devices on the cell middle and cell near, whereN₁ is greater than N₂. For example, the defined number of mobile devicescan be ½ the mobile devices identified at the cell edge. For example,the defined number of mobile devices can be dependent on the totalnumber of mobile devices at the cell edge, location proximity, orcombinations thereof. Initially each of the defined number of mobiledevices at the cell edge can be assigned 8 antennas for beam generationand each of the mobile devices at the cell middle and cell near can beassigned 4 antennas for beam generation subject to the total number ofantennas N and the distribution of the antennas.

In the event that the SAS 1300 may attempt to power down the CBSD (i.e.,based on transmitting or determining that more than 47 dB of power willbe transmitted in an area), the CBSD can assign more antennas to each ofthe defined number of mobile devices at the cell edge. For example, theCBSD can assign 16 antennas to each of the defined number of mobiledevices. As shown in FIG. 2, the beams will become narrower,non-overlapping, and present less interference from the perspective ofthe SAS.

In addition, the defined number of mobile devices which use 8 or moreantennas can be increased by re-assigning antennas from the antennasassigned to the mobile devices at the cell middle and cell near.

In implementations, the CBSDs can use spatial or location diversity toselect mobile devices at the cell edge which are geographicallyseparated to appear as non-localized interference to the SAS.

In implementations, the CBSDs can use time or temporal diversity toschedule transmissions at different times to appear as non-localizedinterference to the SAS.

In implementations, the CBSDs can use combinations of the abovetechniques to non-localize interference to mitigate the chances of theSAS deallocating the CBSD. Consequently, the CBSD, by proactivelydetermining transmission powers, can generate narrower beams to presentless interference.

In the event that the above techniques are successful, then the CBSDscan gradually lower the number of antennas dedicated to each mobiledevice at the cell edge and increase the number of antennas assigned tomobile devices in the cell middle and cell near.

FIG. 3 is a block diagram of an example of a device 3000 in accordancewith embodiments of this disclosure. The device 3000 may include, but isnot limited to, a processor 3100, a memory/storage 3200, a communicationinterface 3300, applications 3400, and a radio frequency device 3500.The device 3000 may include or implement, for example, any of the CBSDs1110 and 1210 and the mobile devices 1400 and 1410. In animplementation, the memory/storage 3200 may store the number of mobiledevices in each region. The radio frequency device 3500 can include anumber of antennas. The applicable or appropriate CBRD interferencemanagement techniques or methods described herein may be stored in thememory/storage 3200 and executed by the processor 3100 in cooperationwith the memory/storage 3200, the communications interface 3300, theapplications 3400, and the radio frequency device 3500 as appropriate.The device 3000 may include other elements which may be desirable ornecessary to implement the devices, systems, and methods describedherein. However, because such elements and steps are well known in theart, and because they do not facilitate a better understanding of thedisclosed embodiments, a discussion of such elements and steps may notbe provided herein.

FIG. 4 is a block diagram of an example of a device 4000 in accordancewith embodiments of this disclosure. The device 4000 may include, but isnot limited to, a processor 4100, a memory/storage 4200, a communicationinterface 4300, and applications 4400. In an implementation, the device4000 may include a radio frequency device 4500. The device 4000 mayinclude or implement, for example, the SAS 1300. In an implementation,the memory/storage 4200 may store the interference map, spectrumallocations, and other information. SAS interference managementtechniques or methods described herein may be stored in thememory/storage 4200 and executed by the processor 4100 in cooperationwith the memory/storage 4200, the communications interface 4300, theapplications 4400, and the radio frequency device 4500 (when applicable)as appropriate. The device 4000 may include other elements which may bedesirable or necessary to implement the devices, systems, and methodsdescribed herein. However, because such elements and steps are wellknown in the art, and because they do not facilitate a betterunderstanding of the disclosed embodiments, a discussion of suchelements and steps may not be provided herein.

FIG. 5 is a flowchart of an example method 5000 for CBSD interferencemanagement in accordance with embodiments of this disclosure. The method5000 includes: connecting 5100 CBSD(s) to a SAS; granting 5200 CBRSspectrum to each CBSD; determining 5300 number of mobile devices in adefined number of regions in a cell; assigning 5400 a greater number ofantennas to a cell edge region than remaining regions; and assigning5500 at least 8 antennas to a defined number of mobile devices in thecell edge region to mitigate interference at the cell edge region. Forexample, the technique 5000 may be implemented, as applicable andappropriate, by a CBSD such as the CBSDs 1110 and 1210 of FIG. 1, theSAS 1300 of FIG. 1, the processor 3100 of FIG. 3, and the processor 4100of FIG. 4.

The method 5000 includes connecting 5100 CBSD(s) to a SAS and granting5200 CBRS spectrum to each CBSD. CBSDs can power on and establishconnections with the SAS. The SAS can then assign a shared spectrum toeach of the CBSDs.

The method 5000 includes determining 5300 number of mobile devices in adefined number of regions in a cell. A cell or cell coverage area of theCBSD can divided up into a number of regions. For example, the regionscan be identified as cell edge, cell middle, and cell near. The CBSD candetermine the number of mobile devices in each region. The CBSDs can usepower headroom reports from the mobile devices to determine and countthe number of mobile devices in a region.

The method 5000 includes assigning 5400 a greater number of antennas toa cell edge region than remaining regions. The CBSD can assign a numberof antennas to each region based on the number of mobile devices, adefault configuration, or combinations thereof.

The method 5000 includes assigning 5500 at least 8 antennas to a definednumber of mobile devices in the cell edge region to mitigateinterference at the cell edge region. A defined number of the mobiledevices in a cell edge region can be assigned 8 antennas based on thenumber of mobile devices, a default configuration, or combinationsthereof. The remaining mobile devices can be assigned at least 4antennas. The CBSD can assign more antennas to each mobile devicedepending on power transmission levels, potential power transmissionlevels, interference levels or potential interference levels. Forexample, mobile devices assigned with 8 antennas can be assigned 16antennas and mobile devices assigned with 4 antennas can be assigned 8antennas. The CBSD can increase the value of the defined number ofmobile devices so that a greater number of the mobile devices have 8 ormore antennas. The CBSD can use spatial diversity to spread out beamtransmission locations. The CBSD can use time diversity to spread outbeam transmission times at a location. The CBSD can use combinations ofspatial diversity and time diversity to spread out beam transmissionlocations and beam transmission times at the beam transmissionlocations.

The description herein describes a method for managing shared spectrumnetwork interference. The method includes determining, by a CitizensBroadband Radio Service (CBRS) device (CBSD) granted shared spectrum bya spectrum access system (SAS), a number of mobile devices in a definednumber of regions in a cell covered by the CBSD, assigning, by the CBSD,a greater number of antennas to a cell edge region from the definednumber of regions than a remaining regions in the defined number ofregions, and assigning, by the CBSD, at least 8 antennas to each mobiledevice of a defined number of mobile devices of the number of mobiledevices in the cell edge region to transmit non-overlapping anddirective beams to mitigate interference at the cell edge region.

The method further includes assigning, by the CBSD, 4 antennas to eachmobile device in the remaining regions. The method further includesassigning, by the CBSD, 4 antennas to each remaining mobile device inthe cell edge region. The method further includes receiving, by the CBSDfrom mobile devices in the cell, power headroom reports, and using, bythe CBSD, a value in the power headroom report to indicate anappropriate region from the defined number of regions. The methodfurther includes assigning, by the CBSD, more antennas to each mobiledevice with 8 antennas to mitigate the interference at the cell edgeregion. The method further includes assigning, by the CBSD, moreantennas to each mobile device with 4 antennas to mitigate theinterference at the cell edge region. The method further includes using,by the CBSD, spatial diversity to select geographically separated mobiledevices to mitigate the interference at the cell edge region. The methodfurther includes using, by the CBSD, time diversity to scheduletransmissions at different times to a location to mitigate theinterference at the cell edge region. The method further includes using,by the CBSD, a combination of spatial diversity and time diversity toschedule transmissions to mitigate interference at the cell edge region.

The description herein describes a Citizens Broadband Radio Service(CBRS) device (CBSD). The CBSD includes a plurality of antennas and aprocessor. The processor is configured to receive shared spectrumallocation from a spectrum access system (SAS), receive power headroomreports from mobile devices in a coverage area of the CBSD, determinedistribution of mobile devices located at an edge of the coverage areaand at non-edges of the coverage area, unevenly distribute antennaassignments between mobile devices at the edge and mobile devices at thenon-edge mobile based on the distribution of the mobile devices, andassign 8 antennas from the plurality of antennas to each mobile deviceof a certain percentage of mobile devices located at the edge of thecoverage area to transmit non-overlapping and directive beams tomitigate interference at the edge of the coverage area.

The processor is further configured to assign 4 antennas from theplurality of antennas to each mobile device of a remaining percentage ofmobile devices at the edge of the coverage area and assign 4 antennasfrom the plurality of antennas to each mobile device at the non-edges ofthe coverage area. The processor is further configured to assign 16antennas from the plurality of antennas to each mobile device at theedge with 8 antennas to mitigate increased interference at the edge andassign 8 antennas from the plurality of antennas to each mobile deviceat the edge with 4 antennas to mitigate the increased interference atthe edge. The processor is further configured to perform at least one ofspatial diversity to select geographically separated mobile devices tomitigate the interference at the cell edge region and time diversity toschedule transmissions at different times to a location to mitigate theinterference at the cell edge region.

The description herein describes a method for managing shared spectrumnetwork interference. The method includes determining, by a sharedspectrum base station for a coverage area, a number of mobile devices atan edge area, a number of mobile devices at a middle area, and a numberof mobile devices at a near area, associating, by the shared spectrumbase station, N antennas to the edge area and M antennas to the middlearea plus the near area, wherein N is greater than M, and associating,by the shared spectrum base station, at least 8 antennas of the Nantennas to each mobile device in a subset of the number of mobiledevices at the edge area to transmit non-overlapping and directive beamsto mitigate interference at the edge area.

The method further includes receiving, by the shared spectrum basestation from mobile devices in the coverage area, power headroom reportsand using, by the shared spectrum base station, a value in the powerheadroom report to indicate one of the edge area, the middle area, andthe near area. The method further includes associating, by the sharedspectrum base station, 16 antennas to each mobile device which have 8antennas assigned to mitigate the interference at the cell edge region.The method further includes associating, by the shared spectrum basestation, 8 antennas to each mobile device with 4 antennas to mitigatethe interference at the edge area. The method further includes using, bythe shared spectrum base station, spatial diversity to selectgeographically separated mobile devices to mitigate the interference atthe edge area. The method further includes using, by the shared spectrumbase station, time diversity to schedule transmissions at differenttimes to a location to mitigate the interference at the edge area. Themethod further includes using, by the shared spectrum base station, acombination of spatial diversity and time diversity to scheduletransmissions to mitigate the interference at the edge area.

Although some embodiments herein refer to methods, it will beappreciated by one skilled in the art that they may also be embodied asa system or computer program product. Accordingly, aspects of thepresent invention may take the form of an entirely hardware embodiment,an entirely software embodiment (including firmware, resident software,micro-code, etc.) or an embodiment combining software and hardwareaspects that may all generally be referred to herein as a “processor,”“device,” or “system.” Furthermore, aspects of the present invention maytake the form of a computer program product embodied in one or more thecomputer readable mediums having the computer readable program codeembodied thereon. Any combination of one or more computer readablemediums may be utilized. The computer readable medium may be a computerreadable signal medium or a computer readable storage medium. A computerreadable storage medium may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, orsemiconductor system, apparatus, or device, or any suitable combinationof the foregoing. More specific examples (a non-exhaustive list) of thecomputer-readable storage medium include the following: an electricalconnection having one or more wires, a portable computer diskette, ahard disk, a random access memory (RAM), a read-only memory (ROM), anerasable programmable read-only memory (EPROM or Flash memory), anoptical fiber, a portable compact disc read-only memory (CD-ROM), anoptical storage device, a magnetic storage device, or any suitablecombination of the foregoing. In the context of this document, acomputer-readable storage medium may be any tangible medium that cancontain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electromagnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to CDs, DVDs,wireless, wireline, optical fiber cable, RF, etc., or any suitablecombination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions.

These computer program instructions may be provided to a processor of ageneral purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer program instructions may also bestored in a computer readable medium that can direct a computer, otherprogrammable data processing apparatus, or other devices to function ina particular manner, such that the instructions stored in the computerreadable medium produce an article of manufacture including instructionswhich implement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowcharts and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures.

While the disclosure has been described in connection with certainembodiments, it is to be understood that the disclosure is not to belimited to the disclosed embodiments but, on the contrary, is intendedto cover various modifications, combinations, and equivalentarrangements included within the scope of the appended claims, whichscope is to be accorded the broadest interpretation so as to encompassall such modifications and equivalent structures as is permitted underthe law.

What is claimed is:
 1. A method for managing shared spectrum networkinterference, the method comprising: determining, by a CitizensBroadband Radio Service (CBRS) device (CBSD) granted shared spectrum bya spectrum access system (SAS), a number of mobile devices in a definednumber of regions in a cell covered by the CBSD; assigning, by the CBSD,a greater number of antennas to a cell edge region from the definednumber of regions than a remaining regions in the defined number ofregions; assigning, by the CBSD, at least 8 antennas to each mobiledevice of a defined number of mobile devices of the number of mobiledevices in the cell edge region to transmit non-overlapping anddirective beams to mitigate interference at the cell edge region;assigning, by the CBSD, 4 antennas to each mobile device in theremaining regions; and assigning, by the CBSD, 4 antennas to eachremaining mobile device in the cell edge region.
 2. The method of claim1, the method further comprising: receiving, by the CBSD from mobiledevices in the cell, power headroom reports; and using, by the CBSD, avalue in the power headroom report to indicate an appropriate regionfrom the defined number of regions.
 3. The method of claim 2, the methodfurther comprising: assigning, by the CBSD, more antennas to each mobiledevice with 8 antennas to mitigate the interference at the cell edgeregion.
 4. The method of claim 3, the method further comprising:assigning, by the CBSD, more antennas to each mobile device with 4antennas to mitigate the interference at the cell edge region.
 5. Themethod of claim 4, the method further comprising: using, by the CBSD,spatial diversity to select geographically separated mobile devices tomitigate the interference at the cell edge region.
 6. The method ofclaim 5, the method further comprising: using, by the CBSD, timediversity to schedule transmissions at different times to a location tomitigate the interference at the cell edge region.
 7. The method ofclaim 4, the method further comprising: using, by the CBSD, acombination of spatial diversity and time diversity to scheduletransmissions to mitigate interference at the cell edge region.
 8. ACitizens Broadband Radio Service (CBRS) device (CBSD) comprising: aplurality of antennas; and a processor configured to: receive sharedspectrum allocation from a spectrum access system (SAS); receive powerheadroom reports from mobile devices in a coverage area of the CBSD;determine distribution of mobile devices located at an edge of thecoverage area and at non-edges of the coverage area; unevenly distributeantenna assignments between mobile devices at the edge and mobiledevices at the non-edge mobile based on the distribution of the mobiledevices; assign 8 antennas from the plurality of antennas to each mobiledevice of a certain percentage of mobile devices located at the edge ofthe coverage area to transmit non-overlapping and directive beams tomitigate interference at the edge of the coverage area; assign 4antennas from the plurality of antennas to each mobile device of aremaining percentage of mobile devices at the edge of the coverage area;and assign 4 antennas from the plurality of antennas to each mobiledevice at the non-edges of the coverage area.
 9. The CBSD of claim 8,the processor further configured to: assign 16 antennas from theplurality of antennas to each mobile device at the edge with 8 antennasto mitigate increased interference at the edge; and assign 8 antennasfrom the plurality of antennas to each mobile device at the edge with 4antennas to mitigate the increased interference at the edge.
 10. TheCBSD of claim 9, the processor further configured to perform at leastone of: spatial diversity to select geographically separated mobiledevices to mitigate the interference at the cell edge region; and timediversity to schedule transmissions at different times to a location tomitigate the interference at the cell edge region.
 11. A method formanaging shared spectrum network interference, the method comprising:determining, by a shared spectrum base station for a coverage area, anumber of mobile devices at an edge area, a number of mobile devices ata middle area, and a number of mobile devices at a near area;associating, by the shared spectrum base station, N antennas to the edgearea and M antennas to the middle area plus the near area, wherein N isgreater than M; associating, by the shared spectrum base station, atleast 8 antennas of the N antennas to each mobile device in a subset ofthe number of mobile devices at the edge area to transmitnon-overlapping and directive beams to mitigate interference at the edgearea; assigning, by the shared spectrum base station, 4 antennas to eachmobile device in the middle area plus the near area; and assigning, bythe shared spectrum base station, 4 antennas to each remaining mobiledevice in the edge area.
 12. The method of claim 11, the method furthercomprising: receiving, by the shared spectrum base station from mobiledevices in the coverage area, power headroom reports; and using, by theshared spectrum base station, a value in the power headroom report toindicate one of the edge area, the middle area, and the near area. 13.The method of claim 11, the method further comprising: associating, bythe shared spectrum base station, 16 antennas to each mobile devicewhich have 8 antennas assigned to mitigate the interference at the edgearea.
 14. The method of claim 13, the method further comprising:associating, by the shared spectrum base station, 8 antennas to eachmobile device with 4 antennas to mitigate the interference at the edgearea.
 15. The method of claim 14, the method further comprising: using,by the shared spectrum base station, spatial diversity to selectgeographically separated mobile devices to mitigate the interference atthe edge area.
 16. The method of claim 14, the method furthercomprising: using, by the shared spectrum base station, time diversityto schedule transmissions at different times to a location to mitigatethe interference at the edge area.
 17. The method of claim 14, themethod further comprising: using, by the shared spectrum base station, acombination of spatial diversity and time diversity to scheduletransmissions to mitigate the interference at the edge area.